My name is Nikolai Beilharz, and I've got something embarrassing to admit.

I waste food.

Now I don't do it on purpose, and it doesn't happen often, but from time to time I'll open the fridge, see some old food, and find myself tipping leftovers into the bin.

Those actions got me thinking. If I'm wasting a bit of food here, and a bit there, and my neighbour does it, and so does theirs, and so does theirs... that adds up pretty quickly.

So as the worlds population continues to grow and there are more mouths to feed, how big is this problem at a global scale?

Upon taking a closer look at the issue, it became apparent just how complex it is, and how many different layers there are.

Waste on the farm

The logical place to begin seems to be where this food is grown - on the farm.

Mike Redmond is the head of South Australia's main vegetable farmer group, Grow SA.

Mr. Redmond says food waste can be an issue for farmers, who can struggle to meet supermarket specification on size, shape and even colour of food.

"Size is one that we come across quite often, people say this doesn't quite make the size for what supermarket orders are, but the product is perfect apart from that."

As reporters we occasionally hear of farmers that have had to plough their crops back in to the ground because the economics don't make sense to harvest the crop.

Mike Redmond from Grow SA says this does occur, and when it does it's a real shame.

"Farmers ploughing their crops back in to the ground because they don't meet specifications happens too often. It doesn't happen every day, but it does happen way too often. To turn it back into the paddock... it's a waste, and just another cost for farmers to bear."

So what can be done to try and minimise that risk? Growers have been trying to find ways to 'value-add' their products, by turning seconds fruit into juices or fruit wraps.

"We even had our guys cut up and package pumpkin that was a bit marked, and so couldn't be sold at the supermarkets. But they cut it up into roasting sized cubes, and instead of getting 20 cents a kilo for the pumpkin they were getting a dollar."

The big picture

If there is significant waste happening on the consumer and farm level, just how bad is the problem globally?

They claim that up to a third of all food that's grown and produced is never eaten.

Gavin Wall, the sub-regional coordinator for the UNFAO says that the waste falls into two distinct categories.

How much food is wasted in Australia?

Australians are throwing away food worth $5.2 billion a year, with the average household wasting $616 of food a year.

Australians waste close to 3 million tonnes of food per annum, or 136 kilos per person per year

Australians discard up to 20% of the food they purchase, which is 1 out of every 5 bags of groceries they buy

An estimated 20 to 40% of fruit and vegetables rejected even before they reach the shops

Throwing away a kilo of beef also throws away the 50,000 litres of water it took to produce that meat, throwing out a kilo of white rice uses 2,385 litres, and wasting a kilo of potatoes uses 500 litres

In the developing world, Mr. Wall says food isn't wasted as much as lost due to poor power and infrastructure.

"Somewhere between the farm and the consumer, the food was lost, it physically deteriorated. Maybe it couldn't be kept in a cool store, perhaps the storage was inadequate, and that food spoils."

It's a different story for developed nations like Australia though, where very little food is lost in the trip from the farm to the supermarket.

Mr. Wall says the waste that occurs in the first world is because consumers throw away food that is fine to eat.

"To a certain extent, we know how to solve the problem in low income economies, you can provide the infrastructure to help that... when you're talking about changing consumer behaviour that can actually be quite difficult."

So where do the solutions lie? Gavin Wall says that people just talking about the issue and bringing it to a more prominent position in society is vital, and says that more government support on reducing waste would go a long way.

Finding a local solution

When faced with such a significant problem, how do you even start to try and reduce waste? A local not for profit group is trying to convince consumers to try and cut down how much they're wasting by talking to them at the fruit and vegetable markets.

Hayley Everuss is state co-ordinator of the group OzHarvest. She says that when you start to dig into how much food is wasted it becomes very concerning.

"The sad truth is it that food waste happens because we can afford it to happen. We can afford to waste food, and that's become a norm in our society."

Hayley Everuss, OzHarvest

"The sad truth is it that food waste happens because we can afford it to happen. We can afford to waste food, and that's become a norm in our society."

Ms. Everuss says that we live too religiously by things like use-by dates.

"We have this thought that at midnight on the 24th of May, the milk will suddenly go off. We need to get back to actually smelling the milk and judging whether it's still good or not instead of throwing it away as a default."

The group has recently launched a 'Too Good to Waste' campaign, which it hopes will start to turn the tide.

The program invites celebrity chefs to perform cooking demonstrations at fruit and vegetable markets to show how food that would otherwise be thrown away can be reused or worked into fresh meals.

"We're here at the markets, just trying to get people to think about their food. We're using a well known chef and pushing the boundaries of how to use ingredients to their full potential. We're just trying to spread the word."